LEVI & KORSINSKY, LLP: RARE STOCK DECLINED OVER 42% FOLLOWING PHASE III STUDY FAILURE DISCLOSURE

Alert: Claims Focus on Alleged Misrepresentations About Setrusumab Efficacy Potential

NEW YORK, March 4, 2026 /PRNewswire/ -- Levi & Korsinsky, LLP reminds purchasers of Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) securities of a pending securities class action. Investors have until April 6, 2026 to seek lead plaintiff status.

THE CASE: A class action seeks to recover damages for investors who purchased Ultragenyx securities between August 3, 2023 and December 26, 2025.

YOUR OPTIONS: You may be entitled to compensation without payment of any out-of-pocket fees.

See if you can recover losses or contact Joseph E. Levi, Esq. at [email protected] | (212) 363-7500.

The December 29, 2025 Stock Collapse

From a closing price of $34.19 on December 26, 2025, Ultragenyx shares plummeted to $19.72 on December 29, 2025---a decline of approximately 42.32%---as the Company disclosed that both Phase III Orbit and Cosmic studies failed to achieve statistical significance against their primary endpoints of reduced annualized fracture rates.

Alleged Stock Drop Impact by the Numbers

• December 2025 Disclosure: Stock fell from $34.19 to $19.72, a 42.32% single-day decline
• July 2025 Interim Results: Stock previously dropped from $41.44 to $31.03, approximately 25.12% in one day
• Combined Class Period losses allegedly reflect removal of artificial inflation from repeated confidence statements
• The filing states analysts cut price targets by more than 30% following the December disclosure
• As set forth in the complaint, the Company announced it would implement "significant expense reductions" following the study failures

Start your claim now or call (212) 363-7500.

What the Corrective Disclosure Revealed

It is alleged that the December 29, 2025 disclosure revealed critical information previously concealed from investors: while setrusumab achieved bone mineral density improvements, these "were not accompanied by a corresponding reduction in annualized fracture rates." The Company attributed the failure to a "low fracture rate in the placebo group" in Orbit and a trend that "did not meet statistical significance" in Cosmic.

"The complaint raises serious questions about whether investors received accurate information about clinical trial risks and variability challenges," said Joseph E. Levi, Esq. "Our team is thoroughly investigating these claims on behalf of affected shareholders."

Levi & Korsinsky, LLP --- Top 50 securities litigation firm (ISS Securities Class Action Services, seven consecutive years). Over 70 professionals. Hundreds of millions recovered for investors nationwide.

CONTACT:

Levi & Korsinsky, LLP

Joseph E. Levi, Esq.

33 Whitehall Street, 27th Floor

New York, NY 10004

(212) 363-7500

[email protected]

www.zlk.com

SOURCE Levi & Korsinsky, LLP